1 | // -*- C++ -*- |
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2 | |
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3 | //run gyorsan tudna adni a minmincutot a 2 fazis elejen , ne vegyuk be konstruktorba egy cutmapet? |
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4 | //constzero jo igy? |
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5 | |
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6 | //majd marci megmondja betegyem-e bfs-t meg resgraphot |
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7 | |
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8 | /* |
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9 | Heuristics: |
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10 | 2 phase |
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11 | gap |
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12 | list 'level_list' on the nodes on level i implemented by hand |
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13 | stack 'active' on the active nodes on level i implemented by hand |
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14 | runs heuristic 'highest label' for H1*n relabels |
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15 | runs heuristic 'bound decrease' for H0*n relabels, starts with 'highest label' |
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16 | |
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17 | Parameters H0 and H1 are initialized to 20 and 10. |
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18 | |
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19 | Constructors: |
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20 | |
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21 | Preflow(Graph, Node, Node, CapMap, FlowMap, bool) : bool must be false if |
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22 | FlowMap is not constant zero, and should be true if it is |
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23 | |
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24 | Members: |
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25 | |
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26 | void run() |
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27 | |
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28 | T flowValue() : returns the value of a maximum flow |
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29 | |
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30 | void minMinCut(CutMap& M) : sets M to the characteristic vector of the |
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31 | minimum min cut. M should be a map of bools initialized to false. |
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32 | |
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33 | void maxMinCut(CutMap& M) : sets M to the characteristic vector of the |
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34 | maximum min cut. M should be a map of bools initialized to false. |
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35 | |
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36 | void minCut(CutMap& M) : sets M to the characteristic vector of |
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37 | a min cut. M should be a map of bools initialized to false. |
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38 | |
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39 | FIXME reset |
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40 | |
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41 | */ |
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42 | |
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43 | #ifndef HUGO_PREFLOW_PROBA_H |
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44 | #define HUGO_PREFLOW_PROBA_H |
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45 | |
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46 | #define H0 20 |
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47 | #define H1 1 |
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48 | |
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49 | #include <vector> |
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50 | #include <queue> |
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51 | #include<graph_wrapper.h> |
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52 | |
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53 | namespace hugo { |
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54 | |
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55 | template <typename Graph, typename T, |
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56 | typename CapMap=typename Graph::EdgeMap<T>, |
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57 | typename FlowMap=typename Graph::EdgeMap<T> > |
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58 | class PreflowProba { |
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59 | |
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60 | typedef typename Graph::Node Node; |
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61 | typedef typename Graph::Edge Edge; |
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62 | typedef typename Graph::NodeIt NodeIt; |
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63 | typedef typename Graph::OutEdgeIt OutEdgeIt; |
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64 | typedef typename Graph::InEdgeIt InEdgeIt; |
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65 | |
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66 | const Graph& G; |
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67 | Node s; |
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68 | Node t; |
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69 | const CapMap& capacity; |
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70 | FlowMap& flow; |
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71 | T value; |
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72 | bool constzero; |
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73 | bool res; |
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74 | |
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75 | typedef ResGraphWrapper<const Graph, T, CapMap, FlowMap> ResGW; |
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76 | typedef typename ResGW::OutEdgeIt ResOutEdgeIt; |
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77 | typedef typename ResGW::InEdgeIt ResInEdgeIt; |
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78 | typedef typename ResGW::Edge ResEdge; |
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79 | |
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80 | public: |
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81 | PreflowProba(Graph& _G, Node _s, Node _t, CapMap& _capacity, |
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82 | FlowMap& _flow, bool _constzero, bool _res ) : |
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83 | G(_G), s(_s), t(_t), capacity(_capacity), flow(_flow), constzero(_constzero), res(_res) {} |
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84 | |
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85 | |
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86 | void run() { |
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87 | |
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88 | ResGW res_graph(G, capacity, flow); |
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89 | |
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90 | value=0; //for the subsequent runs |
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91 | |
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92 | bool phase=0; //phase 0 is the 1st phase, phase 1 is the 2nd |
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93 | int n=G.nodeNum(); |
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94 | int heur0=(int)(H0*n); //time while running 'bound decrease' |
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95 | int heur1=(int)(H1*n); //time while running 'highest label' |
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96 | int heur=heur1; //starting time interval (#of relabels) |
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97 | bool what_heur=1; |
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98 | /* |
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99 | what_heur is 0 in case 'bound decrease' |
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100 | and 1 in case 'highest label' |
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101 | */ |
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102 | bool end=false; |
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103 | /* |
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104 | Needed for 'bound decrease', 'true' |
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105 | means no active nodes are above bound b. |
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106 | */ |
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107 | int relabel=0; |
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108 | int k=n-2; //bound on the highest level under n containing a node |
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109 | int b=k; //bound on the highest level under n of an active node |
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110 | |
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111 | typename Graph::NodeMap<int> level(G,n); |
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112 | typename Graph::NodeMap<T> excess(G); |
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113 | |
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114 | std::vector<Node> active(n-1,INVALID); |
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115 | typename Graph::NodeMap<Node> next(G,INVALID); |
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116 | //Stack of the active nodes in level i < n. |
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117 | //We use it in both phases. |
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118 | |
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119 | typename Graph::NodeMap<Node> left(G,INVALID); |
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120 | typename Graph::NodeMap<Node> right(G,INVALID); |
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121 | std::vector<Node> level_list(n,INVALID); |
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122 | /* |
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123 | List of the nodes in level i<n. |
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124 | */ |
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125 | |
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126 | |
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127 | if ( constzero ) { |
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128 | |
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129 | /*Reverse_bfs from t, to find the starting level.*/ |
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130 | level.set(t,0); |
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131 | std::queue<Node> bfs_queue; |
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132 | bfs_queue.push(t); |
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133 | |
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134 | while (!bfs_queue.empty()) { |
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135 | |
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136 | Node v=bfs_queue.front(); |
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137 | bfs_queue.pop(); |
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138 | int l=level[v]+1; |
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139 | |
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140 | InEdgeIt e; |
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141 | for(G.first(e,v); G.valid(e); G.next(e)) { |
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142 | Node w=G.tail(e); |
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143 | if ( level[w] == n && w != s ) { |
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144 | bfs_queue.push(w); |
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145 | Node first=level_list[l]; |
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146 | if ( G.valid(first) ) left.set(first,w); |
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147 | right.set(w,first); |
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148 | level_list[l]=w; |
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149 | level.set(w, l); |
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150 | } |
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151 | } |
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152 | } |
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153 | |
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154 | //the starting flow |
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155 | OutEdgeIt e; |
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156 | for(G.first(e,s); G.valid(e); G.next(e)) |
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157 | { |
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158 | T c=capacity[e]; |
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159 | if ( c == 0 ) continue; |
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160 | Node w=G.head(e); |
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161 | if ( level[w] < n ) { |
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162 | if ( excess[w] == 0 && w!=t ) { |
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163 | next.set(w,active[level[w]]); |
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164 | active[level[w]]=w; |
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165 | } |
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166 | flow.set(e, c); |
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167 | excess.set(w, excess[w]+c); |
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168 | } |
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169 | } |
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170 | } |
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171 | else |
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172 | { |
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173 | |
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174 | /* |
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175 | Reverse_bfs from t in the residual graph, |
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176 | to find the starting level. |
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177 | */ |
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178 | level.set(t,0); |
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179 | std::queue<Node> bfs_queue; |
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180 | bfs_queue.push(t); |
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181 | |
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182 | while (!bfs_queue.empty()) { |
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183 | |
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184 | Node v=bfs_queue.front(); |
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185 | bfs_queue.pop(); |
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186 | int l=level[v]+1; |
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187 | |
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188 | InEdgeIt e; |
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189 | for(G.first(e,v); G.valid(e); G.next(e)) { |
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190 | if ( capacity[e] == flow[e] ) continue; |
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191 | Node w=G.tail(e); |
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192 | if ( level[w] == n && w != s ) { |
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193 | bfs_queue.push(w); |
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194 | Node first=level_list[l]; |
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195 | if ( G.valid(first) ) left.set(first,w); |
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196 | right.set(w,first); |
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197 | level_list[l]=w; |
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198 | level.set(w, l); |
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199 | } |
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200 | } |
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201 | |
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202 | OutEdgeIt f; |
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203 | for(G.first(f,v); G.valid(f); G.next(f)) { |
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204 | if ( 0 == flow[f] ) continue; |
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205 | Node w=G.head(f); |
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206 | if ( level[w] == n && w != s ) { |
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207 | bfs_queue.push(w); |
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208 | Node first=level_list[l]; |
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209 | if ( G.valid(first) ) left.set(first,w); |
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210 | right.set(w,first); |
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211 | level_list[l]=w; |
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212 | level.set(w, l); |
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213 | } |
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214 | } |
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215 | } |
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216 | |
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217 | |
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218 | /* |
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219 | Counting the excess |
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220 | */ |
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221 | NodeIt v; |
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222 | for(G.first(v); G.valid(v); G.next(v)) { |
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223 | T exc=0; |
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224 | |
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225 | InEdgeIt e; |
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226 | for(G.first(e,v); G.valid(e); G.next(e)) exc+=flow[e]; |
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227 | OutEdgeIt f; |
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228 | for(G.first(f,v); G.valid(f); G.next(f)) exc-=flow[e]; |
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229 | |
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230 | excess.set(v,exc); |
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231 | |
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232 | //putting the active nodes into the stack |
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233 | int lev=level[v]; |
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234 | if ( exc > 0 && lev < n ) { |
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235 | next.set(v,active[lev]); |
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236 | active[lev]=v; |
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237 | } |
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238 | } |
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239 | |
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240 | |
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241 | //the starting flow |
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242 | OutEdgeIt e; |
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243 | for(G.first(e,s); G.valid(e); G.next(e)) |
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244 | { |
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245 | T rem=capacity[e]-flow[e]; |
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246 | if ( rem == 0 ) continue; |
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247 | Node w=G.head(e); |
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248 | if ( level[w] < n ) { |
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249 | if ( excess[w] == 0 && w!=t ) { |
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250 | next.set(w,active[level[w]]); |
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251 | active[level[w]]=w; |
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252 | } |
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253 | flow.set(e, capacity[e]); |
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254 | excess.set(w, excess[w]+rem); |
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255 | } |
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256 | } |
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257 | |
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258 | InEdgeIt f; |
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259 | for(G.first(f,s); G.valid(f); G.next(f)) |
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260 | { |
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261 | if ( flow[f] == 0 ) continue; |
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262 | Node w=G.head(f); |
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263 | if ( level[w] < n ) { |
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264 | if ( excess[w] == 0 && w!=t ) { |
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265 | next.set(w,active[level[w]]); |
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266 | active[level[w]]=w; |
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267 | } |
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268 | excess.set(w, excess[w]+flow[f]); |
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269 | flow.set(f, 0); |
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270 | } |
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271 | } |
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272 | } |
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273 | |
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274 | |
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275 | |
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276 | |
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277 | /* |
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278 | End of preprocessing |
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279 | */ |
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280 | |
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281 | |
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282 | |
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283 | /* |
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284 | Push/relabel on the highest level active nodes. |
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285 | */ |
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286 | while ( true ) { |
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287 | |
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288 | if ( b == 0 ) { |
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289 | if ( phase ) break; |
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290 | |
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291 | if ( !what_heur && !end && k > 0 ) { |
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292 | b=k; |
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293 | end=true; |
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294 | } else { |
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295 | phase=1; |
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296 | level.set(s,0); |
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297 | std::queue<Node> bfs_queue; |
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298 | bfs_queue.push(s); |
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299 | |
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300 | while (!bfs_queue.empty()) { |
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301 | |
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302 | Node v=bfs_queue.front(); |
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303 | bfs_queue.pop(); |
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304 | int l=level[v]+1; |
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305 | |
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306 | if (res){ |
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307 | ResInEdgeIt e; |
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308 | for(res_graph.first(e,v); res_graph.valid(e); |
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309 | res_graph.next(e)) { |
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310 | Node u=res_graph.tail(e); |
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311 | if ( level[u] >= n ) { |
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312 | bfs_queue.push(u); |
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313 | level.set(u, l); |
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314 | if ( excess[u] > 0 ) { |
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315 | next.set(u,active[l]); |
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316 | active[l]=u; |
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317 | } |
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318 | } |
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319 | } |
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320 | } else { |
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321 | InEdgeIt e; |
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322 | for(G.first(e,v); G.valid(e); G.next(e)) { |
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323 | if ( capacity[e] == flow[e] ) continue; |
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324 | Node u=G.tail(e); |
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325 | if ( level[u] >= n ) { |
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326 | bfs_queue.push(u); |
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327 | level.set(u, l); |
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328 | if ( excess[u] > 0 ) { |
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329 | next.set(u,active[l]); |
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330 | active[l]=u; |
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331 | } |
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332 | } |
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333 | } |
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334 | |
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335 | OutEdgeIt f; |
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336 | for(G.first(f,v); G.valid(f); G.next(f)) { |
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337 | if ( 0 == flow[f] ) continue; |
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338 | Node u=G.head(f); |
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339 | if ( level[u] >= n ) { |
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340 | bfs_queue.push(u); |
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341 | level.set(u, l); |
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342 | if ( excess[u] > 0 ) { |
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343 | next.set(u,active[l]); |
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344 | active[l]=u; |
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345 | } |
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346 | } |
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347 | } |
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348 | } |
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349 | } |
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350 | b=n-2; |
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351 | } |
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352 | |
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353 | } |
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354 | |
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355 | |
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356 | if ( !G.valid(active[b]) ) --b; |
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357 | else { |
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358 | end=false; |
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359 | |
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360 | Node w=active[b]; |
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361 | active[b]=next[w]; |
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362 | int lev=level[w]; |
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363 | T exc=excess[w]; |
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364 | int newlevel=n; //bound on the next level of w |
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365 | |
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366 | OutEdgeIt e; |
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367 | for(G.first(e,w); G.valid(e); G.next(e)) { |
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368 | |
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369 | if ( flow[e] == capacity[e] ) continue; |
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370 | Node v=G.head(e); |
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371 | //e=wv |
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372 | |
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373 | if( lev > level[v] ) { |
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374 | /*Push is allowed now*/ |
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375 | |
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376 | if ( excess[v]==0 && v!=t && v!=s ) { |
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377 | int lev_v=level[v]; |
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378 | next.set(v,active[lev_v]); |
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379 | active[lev_v]=v; |
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380 | } |
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381 | |
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382 | T cap=capacity[e]; |
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383 | T flo=flow[e]; |
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384 | T remcap=cap-flo; |
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385 | |
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386 | if ( remcap >= exc ) { |
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387 | /*A nonsaturating push.*/ |
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388 | |
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389 | flow.set(e, flo+exc); |
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390 | excess.set(v, excess[v]+exc); |
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391 | exc=0; |
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392 | break; |
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393 | |
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394 | } else { |
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395 | /*A saturating push.*/ |
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396 | |
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397 | flow.set(e, cap); |
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398 | excess.set(v, excess[v]+remcap); |
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399 | exc-=remcap; |
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400 | } |
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401 | } else if ( newlevel > level[v] ){ |
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402 | newlevel = level[v]; |
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403 | } |
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404 | |
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405 | } //for out edges wv |
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406 | |
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407 | |
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408 | if ( exc > 0 ) { |
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409 | InEdgeIt e; |
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410 | for(G.first(e,w); G.valid(e); G.next(e)) { |
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411 | |
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412 | if( flow[e] == 0 ) continue; |
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413 | Node v=G.tail(e); |
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414 | //e=vw |
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415 | |
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416 | if( lev > level[v] ) { |
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417 | /*Push is allowed now*/ |
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418 | |
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419 | if ( excess[v]==0 && v!=t && v!=s ) { |
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420 | int lev_v=level[v]; |
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421 | next.set(v,active[lev_v]); |
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422 | active[lev_v]=v; |
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423 | } |
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424 | |
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425 | T flo=flow[e]; |
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426 | |
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427 | if ( flo >= exc ) { |
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428 | /*A nonsaturating push.*/ |
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429 | |
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430 | flow.set(e, flo-exc); |
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431 | excess.set(v, excess[v]+exc); |
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432 | exc=0; |
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433 | break; |
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434 | } else { |
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435 | /*A saturating push.*/ |
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436 | |
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437 | excess.set(v, excess[v]+flo); |
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438 | exc-=flo; |
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439 | flow.set(e,0); |
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440 | } |
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441 | } else if ( newlevel > level[v] ) { |
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442 | newlevel = level[v]; |
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443 | } |
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444 | } //for in edges vw |
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445 | |
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446 | } // if w still has excess after the out edge for cycle |
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447 | |
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448 | excess.set(w, exc); |
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449 | |
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450 | /* |
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451 | Relabel |
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452 | */ |
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453 | |
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454 | |
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455 | if ( exc > 0 ) { |
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456 | //now 'lev' is the old level of w |
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457 | |
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458 | if ( phase ) { |
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459 | level.set(w,++newlevel); |
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460 | next.set(w,active[newlevel]); |
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461 | active[newlevel]=w; |
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462 | b=newlevel; |
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463 | } else { |
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464 | //unlacing starts |
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465 | Node right_n=right[w]; |
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466 | Node left_n=left[w]; |
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467 | |
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468 | if ( G.valid(right_n) ) { |
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469 | if ( G.valid(left_n) ) { |
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470 | right.set(left_n, right_n); |
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471 | left.set(right_n, left_n); |
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472 | } else { |
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473 | level_list[lev]=right_n; |
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474 | left.set(right_n, INVALID); |
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475 | } |
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476 | } else { |
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477 | if ( G.valid(left_n) ) { |
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478 | right.set(left_n, INVALID); |
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479 | } else { |
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480 | level_list[lev]=INVALID; |
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481 | } |
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482 | } |
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483 | //unlacing ends |
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484 | |
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485 | if ( !G.valid(level_list[lev]) ) { |
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486 | |
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487 | //gapping starts |
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488 | for (int i=lev; i!=k ; ) { |
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489 | Node v=level_list[++i]; |
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490 | while ( G.valid(v) ) { |
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491 | level.set(v,n); |
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492 | v=right[v]; |
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493 | } |
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494 | level_list[i]=INVALID; |
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495 | if ( !what_heur ) active[i]=INVALID; |
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496 | } |
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497 | |
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498 | level.set(w,n); |
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499 | b=lev-1; |
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500 | k=b; |
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501 | //gapping ends |
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502 | |
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503 | } else { |
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504 | |
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505 | if ( newlevel == n ) level.set(w,n); |
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506 | else { |
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507 | level.set(w,++newlevel); |
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508 | next.set(w,active[newlevel]); |
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509 | active[newlevel]=w; |
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510 | if ( what_heur ) b=newlevel; |
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511 | if ( k < newlevel ) ++k; //now k=newlevel |
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512 | Node first=level_list[newlevel]; |
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513 | if ( G.valid(first) ) left.set(first,w); |
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514 | right.set(w,first); |
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515 | left.set(w,INVALID); |
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516 | level_list[newlevel]=w; |
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517 | } |
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518 | } |
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519 | |
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520 | |
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521 | ++relabel; |
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522 | if ( relabel >= heur ) { |
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523 | relabel=0; |
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524 | if ( what_heur ) { |
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525 | what_heur=0; |
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526 | heur=heur0; |
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527 | end=false; |
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528 | } else { |
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529 | what_heur=1; |
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530 | heur=heur1; |
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531 | b=k; |
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532 | } |
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533 | } |
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534 | } //phase 0 |
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535 | |
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536 | |
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537 | } // if ( exc > 0 ) |
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538 | |
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539 | |
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540 | } // if stack[b] is nonempty |
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541 | |
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542 | } // while(true) |
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543 | |
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544 | |
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545 | value = excess[t]; |
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546 | /*Max flow value.*/ |
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547 | |
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548 | } //void run() |
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549 | |
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550 | |
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551 | |
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552 | |
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553 | |
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554 | /* |
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555 | Returns the maximum value of a flow. |
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556 | */ |
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557 | |
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558 | T flowValue() { |
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559 | return value; |
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560 | } |
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561 | |
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562 | |
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563 | FlowMap Flow() { |
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564 | return flow; |
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565 | } |
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566 | |
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567 | |
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568 | |
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569 | void Flow(FlowMap& _flow ) { |
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570 | NodeIt v; |
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571 | for(G.first(v) ; G.valid(v); G.next(v)) |
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572 | _flow.set(v,flow[v]); |
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573 | } |
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574 | |
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575 | |
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576 | |
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577 | /* |
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578 | Returns the minimum min cut, by a bfs from s in the residual graph. |
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579 | */ |
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580 | |
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581 | template<typename _CutMap> |
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582 | void minMinCut(_CutMap& M) { |
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583 | |
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584 | std::queue<Node> queue; |
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585 | |
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586 | M.set(s,true); |
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587 | queue.push(s); |
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588 | |
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589 | while (!queue.empty()) { |
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590 | Node w=queue.front(); |
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591 | queue.pop(); |
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592 | |
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593 | OutEdgeIt e; |
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594 | for(G.first(e,w) ; G.valid(e); G.next(e)) { |
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595 | Node v=G.head(e); |
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596 | if (!M[v] && flow[e] < capacity[e] ) { |
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597 | queue.push(v); |
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598 | M.set(v, true); |
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599 | } |
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600 | } |
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601 | |
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602 | InEdgeIt f; |
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603 | for(G.first(f,w) ; G.valid(f); G.next(f)) { |
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604 | Node v=G.tail(f); |
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605 | if (!M[v] && flow[f] > 0 ) { |
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606 | queue.push(v); |
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607 | M.set(v, true); |
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608 | } |
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609 | } |
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610 | } |
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611 | } |
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612 | |
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613 | |
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614 | |
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615 | /* |
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616 | Returns the maximum min cut, by a reverse bfs |
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617 | from t in the residual graph. |
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618 | */ |
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619 | |
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620 | template<typename _CutMap> |
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621 | void maxMinCut(_CutMap& M) { |
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622 | |
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623 | std::queue<Node> queue; |
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624 | |
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625 | M.set(t,true); |
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626 | queue.push(t); |
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627 | |
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628 | while (!queue.empty()) { |
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629 | Node w=queue.front(); |
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630 | queue.pop(); |
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631 | |
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632 | |
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633 | InEdgeIt e; |
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634 | for(G.first(e,w) ; G.valid(e); G.next(e)) { |
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635 | Node v=G.tail(e); |
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636 | if (!M[v] && flow[e] < capacity[e] ) { |
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637 | queue.push(v); |
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638 | M.set(v, true); |
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639 | } |
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640 | } |
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641 | |
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642 | OutEdgeIt f; |
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643 | for(G.first(f,w) ; G.valid(f); G.next(f)) { |
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644 | Node v=G.head(f); |
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645 | if (!M[v] && flow[f] > 0 ) { |
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646 | queue.push(v); |
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647 | M.set(v, true); |
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648 | } |
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649 | } |
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650 | } |
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651 | |
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652 | NodeIt v; |
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653 | for(G.first(v) ; G.valid(v); G.next(v)) { |
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654 | M.set(v, !M[v]); |
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655 | } |
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656 | |
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657 | } |
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658 | |
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659 | |
---|
660 | |
---|
661 | template<typename CutMap> |
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662 | void minCut(CutMap& M) { |
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663 | minMinCut(M); |
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664 | } |
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665 | |
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666 | |
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667 | void reset_target (Node _t) {t=_t;} |
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668 | void reset_source (Node _s) {s=_s;} |
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669 | |
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670 | template<typename _CapMap> |
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671 | void reset_cap (_CapMap _cap) {capacity=_cap;} |
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672 | |
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673 | template<typename _FlowMap> |
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674 | void reset_cap (_FlowMap _flow, bool _constzero) { |
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675 | flow=_flow; |
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676 | constzero=_constzero; |
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677 | } |
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678 | |
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679 | |
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680 | |
---|
681 | }; |
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682 | |
---|
683 | } //namespace hugo |
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684 | |
---|
685 | #endif //PREFLOW_PROBA_H |
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686 | |
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687 | |
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688 | |
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689 | |
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